[rules-users] Drools Fusion deadlock?

Hi, I'm having a problem in my project; inserting large quantities of facts into a StatefulKnowledgeSession (stream mode) causes my code to hang after a few minutes of activity. I've attached a simple test to demonstrate the problem; when I run the attached code ~ 20 objects get inserted into the session, the rule fires once and then hangs. No more facts get inserted and the rule never fires again. Is there anything obvious wrong with the attached code, or is it possible that this is a bug in drools [drools-5.0.1]? Thanks and regards, Paul